In a conventional angiographic unit, an image intensifier receives an X-ray signal if an X-ray is irradiated onto a human body, and transmits the received the X-ray signal to a camera tube, by which the X-ray signal is converted into an image signal. When the image signal is reconfigured by several image-processing circuits and sent to a monitor, an operator performs treatments while watching the monitor. As such, since there are few techniques for reconstructing 3D images in a real-time fluoroscopic field, it is difficult for the operator to recognize accurate pathways, directions, etc. of blood vessels with 2D images upon a treatment.
Upon taking an image of blood vessels by using an angiographic unit, a performance of the angiographic unit is evaluated by a resolving power, which is determined by contrast resolution, time resolution, and spatial resolution. The contrast resolution is an ability of discerning differences between light and darkness of a substance and the time resolution is an ability of discerning a minimum time interval regarding an input signal. The spatial resolution, which is the most important element in determining the resolving power, is an ability to geometrically separate and discern an adjacent substance, but the reconstruction of three-dimension (3D) as an element for improving the spatial resolution is scarcely considered.
To overcome such problems, a method for obtaining 2D images orthogonal with each other by using two C-arms and then reconstructing a 3D structure has been suggested. However, the method has also problems of causing a double radiation exposure due to two X-ray generators and two detectors, and failing to obtain images from various angles.